For video security camera systems, it is desirable to capture high-resolution images for various reasons, such as to be able to recognize the faces of individuals appearing in the images. Security camera systems that capture high-resolution images typically consume relatively large amounts of power, and are usually not battery-powered, or if they are battery-powered, the battery life is relatively short due to the large power consumption. Some security camera systems are also configured to record at all times, rather than only when there is activity, which wastes video tape or digital recording space.
Some security camera systems use passive infrared (PIR) motion detectors to detect motion and trigger a security camera. PIR motion detectors detect radiated energy, such as energy radiated by a human or animal. PIR motion detection devices typically cost about $20, and usually draw ten to twenty milliamps at twelve volts (i.e., 120-240 milliwatts (mW)). A typical nine-volt battery offers 565 milliamp hours (mAH), which would provide about five hours of continual operation for such PIR devices—a relatively short duration.